Localization Studies For Pheochromocytoma

MIBG selectively accumulates in tissues that store catecholamines in neurosecretory granules. The uptake of MIBG into a tissue is proportional to the concentration of neurosecretory granules.34 Scintig-raphy using radioactive iodine (123I)-MIBG or 131I-MIBG is useful for imaging an occult pheochromo-cytoma, paraganglioma, or neuroblastoma or for confirming that a certain mass is a neuroendocrine tumor (Figure 9-4).35 It is also useful for screening patients for metastases. MIBG uptake does...

Somatostatinomas

Somatostatin is a tetradecapeptide gut hormone that inhibits the release or action of almost all other gut hormones, including insulin, glucagon, gastrin, and cholecystokinin. Excessive production of somato-statin by a tumor arising from delta pancreatic islet cells leads to a clinical syndrome featuring steator-rhea, diarrhea, mild diabetes mellitus, cholelithiasis, weight loss, anemia, and hypochlorhydria.34 These are exceedingly rare tumors. In the largest collected series to date describing...

Location And Pathology Of Pheochromocytomas

Most pheochromocytomas are located in the adrenal glands (90 in adults and 70 in children), occurring more frequently on the right than on the left. In one series, right-sided pheochromocytomas have been described as producing paroxysmal hypertension more often than sustained hypertension, whereas the opposite is true for tumors arising from the left adrenal gland.18 Adrenal pheochromocytomas are bilateral in about 10 of adults and 35 of children. They may present at any age but are more common...

Evaluation

The adrenal gland is one of the frequent sites of metastases, and virtually any malignancy may spread to it. A metastatic tumor should be highly suspected in the setting where an imaging study detects an adrenal mass in a patient with a known history of malignant disease. Common cancers that metastasize to the adrenal gland are from the lung, kidney, breast, gastrointestinal tract, and melanoma. Occasionally, an adrenal metastasis is discovered with an undetermined primary origin thus, a...

Fasting Test and Insulinto Glucose Ratio

The most useful diagnostic test is the demonstration of fasting hypoglycemia in the face of inappropriately high levels of insulin in the serum. The patient is fasted, and blood samples are obtained every 6 hours or when symptoms develop for blood glucose and insulin measurements. The fast is continued until hypoglycemia or symptoms appear, or for a maximum of 72 hours. One-third of insulinoma patients become hypoglycemic within 12 hours of fasting, 80 within 24 hours, 90 within 48 hours, and...

Medical Treatment Of Insulinomas Diet

Acute episodes of hypoglycemia are reversed with carbohydrate. Patients frequently learn this practice for themselves before the diagnosis is made and snack frequently. This often results in weight gain. More severe attacks, including coma, require intravenous glucose administration. Many patients with hyperinsulinism find that they do better on a highprotein diet, as do patients with reactive hypo-glycemia. This has added appeal in that the total carbohydrate and fat intake can be decreased,...

Clinical Manifestations

The initial manifestations of parathyroid carcinoma are quite similar to those of the two leading causes of primary hyperparathyroidism nonmalignant parathyroid hyperplasia and parathyroid adenoma. The intensity of the symptoms and manifestations tends to be greater for parathyroid carcinoma than benign lesions, as is the rapidity of onset. Patients with parathyroid carcinoma present more commonly with hypercalcemic crisis and significantly higher levels of hypercalcemia than patients with...

Preoperative Treatment Of Patients With Pheochromocytomas

It is ideal for patients to be hemodynamically stable on oral antihypertensives (see below) prior to surgery. During outpatient titration of antihyperten-sive doses, patients should have daily orthostatic measurements of blood pressure and pulse. Additionally, patients should measure their blood pressure at the time of paroxysmal symptoms. However, prolonged preoperative preparation of greater than 7 days is no more effective at preventing intraoperative hypertension than are shorter...

Subclinical Cushings Syndrome

Preclinical or subclinical Cushing's syndrome is caused by autonomous glucocorticoid secretion in patients who may have no overt, or only minimal, clinical signs and symptoms of full-blown Cushing's syndrome. Subclinical hypercortisolism has been reported in 5 to 20 of patients with adrenal inci-dentalomas. Depending on the amount of glucocor-ticoid secreted by the tumor, the clinical spectrum can vary considerably. Diagnostically, patients often have a slightly attenuated diurnal rhythm of...

Medical Treatment Of Secondary

The factors responsible for the development of secondary HPT, including hypocalcemia, hyperphosphatemia, and vitamin D deficiency, should be corrected.11 Early treatment is of value to prevent bone disease. Overall, only about 5 of patients with chronic renal failure on dialysis require parathyroidectomy. A diet low in phosphorus and high in phosphorus binders should be prescribed to keep serum phosphate levels normal. Phosphate binders containing aluminum hydroxide should be avoided or used...

Thyrotoxicosis

Thyrotoxicosis is a clinical syndrome that results from exposure to increased levels of circulating thy Figure 1-13. In follicular neoplasms, cytology and frozen section examinations are of limited to no value in differentiating between follicular adenoma and adenocarcinoma. Permanent histology with the demonstration of capsular or vessel invasion is necessary to diagnose cancer. A, Photomicrograph showing invasion into but not through the capsule consistent with an atypical follicular adenoma....

History Of Pheochromocytoma

In 1886, Frankel described bilateral adrenal tumors discovered at the autopsy of an 18-year-old woman who died suddenly following a year of retinitis and episodic palpitations, pounding heart, pallor, headaches, and vomiting. Her postmortem examination also revealed nephrosclerosis and myocardial hypertrophy.1 In 1896, Manasse demonstrated that such a tumor turned dark brown when exposed to chromium salts (the chromaffin reaction), a characteristic of adrenal medullary tissue these tumors were...

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Posterior Relation Pancreas

The Success Rates of the Localization Techniques Percent of Patients with True Positive Results Percent of Patients with True Positive Results Figure 13-14. Success rates of insulinoma localization at our institution using various localization techniques. CT computed tomography MRI magnetic resonance imaging THPVS transhep-atic portal venous sampling. Reproduced with permission from Boukhman MB et al.33 tionship to the pancreatic ducts, the portal vein, the common bile duct, and the superior...

Carcinoid

Carcinoid tumors are derived from the embryonic foregut bronchi, thymus, stomach, pancreas, and duodenum , midgut, and hindgut.34 Most MEN type I carcinoids are derived from the foregut 69 .35 They occur in approximately 7 of patients with MEN type I. Foregut tumors produce the carcinoid syndrome less often than midgut tumors. Patients may have an atypical presentation with facial flush, lacrimation, headaches, and or bron-chospasm. Foregut tumors generally do not produce 5-hydroxytryptamine...

Glucagonoma VIPoma Somatostatinoma ECLoma and Nonfunctional Tumors

The role of surgery for nongastrinoma, noninsuli-noma tumors in MEN type I is limited by the availability of safe and effective pharmacologic agents for the palliation of the clinical syndromes. The focus of operative intervention, then, is the management of the potential malignancy. Operatively, the management of patients with glucagonomas, VIPomas, or carcinoid tumors is similar to that of patients with insulinomas. Resection of evident neoplasms appears to be the treatment of choice....

Clinical Manifestation

The signs and symptoms of Cushing's syndrome may be subtle and nonspecific. These clinical manifestations vary depending on the severity and duration of hypercortisolism. Cushing's syndrome Figure 11-1. Hypothalamus-pituitary-adrenal axis. ACTH adreno-corticotropic hormone CRH corticotropin-releasing hormone. Figure 11-1. Hypothalamus-pituitary-adrenal axis. ACTH adreno-corticotropic hormone CRH corticotropin-releasing hormone. Table 11-1. CAUSES OF CUSHING'S SYNDROME Exogenous iatrogenic the...

GRFoma

A GRFoma is an endocrine tumor that produces GH-releasing factor, which causes acromegaly.26 It is a rare tumor, and approximately 30 are associated with MEN type I. These tumors typically occur in the lung 53 , pancreas 30 , or small intestine 10 . Patients are younger, with a mean age of 38. The tumors are often multiple, large, and metastatic. Sixty-five percent of GRFomas are associated with a tumor causing another hormonal syndrome, such as Zollinger-Ellison or Cushing's syndrome.27 The...

Anterior Pituitary Tumorsnance imaging MRI with gadolinium contrast of

Sella, basal GH, prolactin, and urine free cortisol. The reported incidence in MEN type I syndrome Patients may also be screened for gonadotropin- varies from 0 to 100 .716'40 However, pituitary secreting tumor with basal- and thyrotropin- abnormalities may be the first manifestation of releasing hormone-stimulated LH, LH-P, LH-a, MEN type I therefore, screening with prolactin lev- and FSH. Baseline free thyroxine T4 and TSH will els is recommended. There is a 2 to 1 female-to- identify...

Pheochromocytoma Physiology

Pheochromocytomas synthesize catecholamines at a high rate, up to 27 times the normal adrenal medulla.9 Pheochromocytoma cells ordinarily contain more norepinephrine than epinephrine, the opposite of the normal adrenal medulla. In adults, about 90 of pheochromocytomas arise from the adrenal medulla. Pheochromocytomas that secrete epinephrine are even more likely to be located in the adrenal medulla. Paragangliomas rarely secrete epinephrine. The serum concentration of catecholamines does not...

References

Pheochromocytoma. New York 2. Robinson R. Tumours that secrete catecholamines. Their detection and clinical chemistry. New York John Wiley amp Sons 1980. 3. Lack EE. Adrenal medullary hyperplasia and pheochromo cytoma. In Lack EE, editor. Pathology of the adrenal glands. New York Churchill Livingstone 1990. 4. Strombeck JP, Hedberg TP. Tumor of the suprarenal medulla associated with paroxysmal hypertension. Report of a case preoperatively diagnosed and cured by...